There are a few approaches to that.
The content you are referring to would show on the login and the register shortcode pages when the user is a logged in state.
There are filter hooks for the content that is output in that state so you could filter it, change it, or dump it completely and put something else in its place. There is a list of hooks here:
https://rocketgeek.com/plugins/wp-members/users-guide/filter-hooks/
You would be looking specifically at wpmem_login_links and/or wpmem_register_links
Alternatively, both of those page shortcodes can be nested inside the status shortcode. So if you use the page shortcode inside the logged out status shortcode like this:
[wp-members status="out"][wp-members page="login"][/wp-members]
then you could use the logged in status shortcode to display whatever you want to the user when they are in the logged in state. More info on the shortcodes here: https://rocketgeek.com/plugins/wp-members/users-guide/shortcodes/
